JPS6125106Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to automatic music selection in a tape recorder, and more particularly to a plunger drive circuit that can be adapted to various tape mechanisms for automatic music selection.

Generally, in a tape recorder, multiple pieces of music or conversations recorded on magnetic tape are
When a predetermined point, for example a song in the case of music, is automatically selected, so-called automatic song selection is performed by operating the play button and the fast forward or rewind button of the tape recorder to mechanically lock the slide section on which the magnetic head is mounted, setting it to the cue or review state, and counting the song or non-song parts recorded on the magnetic tape. After counting a predetermined number, when the predetermined song part is reached, the lock is released by the action of the plunger, and the playback state is set (the plunger drive signal is as shown in FIG. 1A, hereinafter referred to as Type A), and song selection (meaning a song program, 1 to N
In many cases, the plunger is turned on by operating the play button and the fast forward or rewind button, and after counting the number of song or non-song parts, the plunger is turned off when the specified song part is reached, the cue or review state is released and the playback state is set, and the specified song is played (the plunger drive signal is as shown in Figure 1 (B) and will be referred to as Type B hereafter).

However, there are no plunger drive circuits that can be applied to these two systems, especially integrated circuit (IC) circuits, and when the control circuit, which has recently become full logic, is assembled using MOS transistors as an LSI, it is difficult to combine the music selection circuit and the plunger drive circuit. At the same time, there has been an increasing demand for integration into one chip.

Therefore, the present invention provides a plunger drive circuit that meets the above-mentioned requirements, and is particularly suitable for use as a MOS transistor.

The present invention will be explained below with reference to the drawings. Fig. 2 shows one embodiment of the plunger drive circuit of the present invention, and Fig. 4 shows an embodiment of the plunger drive circuit of the present invention.
The figures show other embodiments of the same circuit, Figures 3 A to 5 and 5.
Figures A and B show the waveforms of each part of FIGS. 2 and 4, respectively.

Next, the circuit shown in FIG. 2, which can be applied to the above-mentioned A type, will be explained using FIG. 3.
1 is a shift register for the program that selects songs;
2, 3, and 4 are light emitting diodes (LEDs) for display;
5 and 6 are P channel MOS transistors, 7 is
NAND gate, 8 is a Schmitt circuit, 9 is a load resistor, 10 is a base resistor, 11 is a switching transistor, 12 is a plunger, 13 is a protection diode, 14 and 15 are resistors forming a time constant circuit for setting the pulse width and a capacitor.

Now, after turning on the power switch as shown in Figure 2,
If you operate the song selection button (program button) provided on the tape recorder and set, for example, Q ₁ = "1", LED 3 lights up in response to this, and at this time, Q ₀ = "0" and the MOS transistor 5 is on, the capacitor 15 is charged, and the potential CR at the terminal 16 is "H".

When a fast forward or rewind operation is performed in this state, the magnetic head slide section is mechanically locked in the queue or review state and is in the song search state.
In this state, one of the input terminals of the NAND gate 7 is "0", the other is "1", and the output terminal is "1", so the MOS transistor 6 is off, and therefore the potential of the terminal 17 is PO is at the "L" level, the switching transistor 11 is off, and the plunger 12 is kept off.

Next, a song is selected at timing t ₁ , and the program shift register 1 is set to Q ₀ =
When it is inverted to "1", the MOS transistor 5 is turned off and the charge in the capacitor 15 is transferred to the resistor 14.
The potential CR at the terminal 16 decreases as shown in FIG _. Since it is "1", all input terminals of the NAND gate 7 become "1", and its output is inverted to "0", so the MOS transistor 6 is turned on and the potential PO of the terminal 17 immediately changes to "1". When the level becomes "H" and the switching transistor 11 is turned on, the plunger 12 operates to release the lock of the slide portion described above, enters the playback state at timing tz, and plays a predetermined song.

In this case, the pulse width corresponding to the time required to drive the plunger, ie (t ₂ -t ₁ ), is set by the resistor 14 and capacitor 15 in consideration of the mechanical response time of the sliding portion.

Next, the embodiment shown in FIG. 4 will be explained.
Switching transistor 1 within the broken line in the figure
1 is an example using a PNP transistor, and NPN
First, to explain an example using a transistor, at the same time as the power switch is turned on, the programming shift register 1 is set to the initial setting, that is, as shown in FIG. 5A, Q ₀ = "1" and the MOS transistor 5 is turned off. , the potential CR of the terminal 16 is set to "L".

After this, select the song, that is, shift register for programming.
When the bits other than Q ₀ of 1 are set to "1" and Q ₀ = "0", the MOS transistor 5 is turned on and the base potential of the switching transistor 11 becomes "H". When fast forwarding or rewinding is performed in this state, the switch 18 linked to the head slide closes, and at the same time, the switching transistor 11 is turned on, the plunger 12 is driven, the cue or review state is set, and the song search state is reached. to go into.

After song selection is performed, Q ₀ =
When it becomes “1”, the potential CR of terminal 16 corresponds to this.
falls, the switching transistor 11 is turned off again, the plunger 12 is turned off, and the tape recorder is set to the playback state, so that the predetermined song will be played back.

On the other hand, when using the circuit shown by the broken line in FIG. 4, it is sufficient to use the change in the potential PO of the terminal 17 when the terminal 16 is set to "1", that is, CR=+V _DD .
If Q ₀ = "1", the output of the NAND gate 7 is "0", so the MOS transistor 6 is on, the switching transistor 11' is off, and the plunger 12 is kept off, and if Q ₀ = "0", then the output of the NAND gate 7 is "0". The output of the NAND gate 7 is "1", so the MOS transistor 6 is turned off, the switching transistor 11' is turned on, and the plunger 12 is also turned on, so that music selection can be performed in the same manner as in the above-mentioned operation.

As described above, according to the present invention, the circuit that generates the signal for driving the plunger shown within the dashed-dot line can be shared by the above-mentioned A type and B type without increasing the number of output terminals, and the circuit inside the dashed-dotted line can be used as a MOS transistor. When integrated into an IC, the plunger and the NPN or
By connecting switching transistors such as PNP, the desired purpose can be achieved with a minimum number of terminals, and the plunger drive circuit of the present invention is extremely useful for automatic music selection devices of tape recorders.

[Brief explanation of the drawing]

Figure 1 A and B are waveform diagrams for explaining the plunger drive circuit of the present invention, Figures 2 and 4 are the same circuits of the present invention, Figure 3 A, B, and C, and Figures 5 A and B. 2 and 4 respectively show the waveforms of the respective parts. 1 ...Program shift register, 5, 6...
...MOS transistor, 7...NAND gate, 8
...Schmitt circuit, 11...switching transistor, 12...plunger.

Claims (1)

[Scope of utility model registration request] Detects a no-signal portion between multiple signal portions of music, etc. recorded on a magnetic tape in fast forward or rewind mode, and releases the fast forward or rewind condition when a set number of no signal portions is detected. In an automatic music selection circuit of a tape recorder that switches to a playback state, a storage control means for storing the preset no-signal portion and counting the plurality of signal portions or no-signal portions is connected to an output terminal of the storage control means. a gate circuit having an input terminal connected to an output terminal of the first switching element and an output terminal of the storage control means, and an output terminal of the gate circuit connected to an input terminal; the output terminal of the second switching element or the output terminal of the first switching element is connected to the input terminal of a switching transistor connected to a plunger as a load, and A plunger drive circuit, characterized in that the plunger drive circuit controls the switching transistor when the switching transistor reaches a preselected signal section.